Non-latex balloons of the type comprising two flexible sheets of plastics material which are sealed together around their periphery in a variety of shapes and have a neck (also referred to as a stem) defining an opening for inflation of the balloon, typically by helium, are extremely popular. One or both of the sheets may be decorated or metallised. U.S. Pat. No. 4,917,646 discloses a self sealing valve in the form of a simple passageway provided between two elongate strips of plastics material which are sealed within the neck of the balloon during manufacture and extend into the space within the balloon. A bonding barrier, which may be provided by a coating on one of the strips, ensures that the passageway is kept open at the inlet during the heat sealing operation. The passageway may be narrowed by convergence between the lines of seal at the respective sides of the passageway, either at one or both sides, for example by a stepped or sloping section of one or both lines of seal, so that the size of the outlet from the valve into the space within the balloon is less than that of the inlet to the valve in the neck of the balloon. Such valves allow inflation of the balloon, but tend to closure so as to prevent escape of gas from the balloon, or at least allow escape of gas at such a reduced rate that the balloon will remain inflated for a sufficient length of time as required by the user, for example at least 24 hours. This is sufficient bearing in mind that such balloons are used mostly for celebratory and party purposes. Most commercially available balloons of this type incorporate this simple self sealing valve arrangement. p Various proposals have been made, for example in U.S. Pat. Nos. 5,795,211, in 5,947,581, in US 2002/0164919, in US 2004/0127138 and in WO 2005/103557 for mounting light emitting devices, specifically light emitting diodes (LEDs) within such balloons, in order to enhance the attractiveness of same. In U.S. Pat. No. 5,795,211, one or more LEDs are attached by adhesive tape to an inner surface of one of the sheets forming the balloon and connected to a battery power source located outside the balloon by way of a pair of flat conductor leads which are embedded in a strip of polyethylene and extend through the neck of the balloon. The polyethylene strip is heat sealed in the neck of the balloon alongside an elongate self-sealing inflation valve of the type described above. In US 2004/0127138 an assembly including an LED, a power supply cell, an electric circuit connecting the cell and the LED and a switch in the circuit, is suspended centrally within the space within the balloon by being mounted upon a strip of plastics material, one end of which is bonded between the respective sheets forming the balloon at one point around their periphery. In the other prior proposals just mentioned, the LED is part of a device which is adhered at a location within the space of the balloon to one of the respective sheets forming the balloon. Such mounting is likely to complicate the production of such balloons and they may not be economically viable.
An object of the present invention is to provide a method of incorporating an LED device or other electronic device into this type of non-latex balloon which does not require significant deviation from the methodology of conventional mass production of such balloons, and requires minimal or no additional assembly steps and is therefore cost-effective.